Our program project represents a highly integrated approach to translate basic science findings on the role of hypoxia in tumor progression and resistance to therapy to pre-clinical models of cancer that we ultimately hope to take into the clinic. The overall hypothesis of this proposal is that hypoxia not only makes tumor cells resistant to therapy, but also increases their invasiveness and metastatic potential by inducing metastatic-related genes such as osteopontin (OPN) and connective tissue growth factor (CTGF). During the last four years, the investigators of this program project have worked together using yeast as well as mammalian cells to understand the genomic response of tumor cells to hypoxia and develop new targeted therapies to eliminate hypoxic cells or inhibit the secreted gene products of hypoxic cells that drive malignant progression. We have advanced understanding of gene regulation under hypoxic conditions, used the yeast deletion pool to identify genetic determinants that are critical for survival under hypoxia as well as other stress inducing conditions, and developed new diagnostics for hypoxia. In the renewal application we will further define critical effectors of the hypoxic response that will be manipulated to increase the effectiveness of new hypoxic cytotoxins as well as inhibit the activity of secreted proteins induced by hypoxia that are essential for tumor growth and expansion. Emphasis is placed on understanding and exploiting the tumor microenvironment of head &neck cancers where overcoming hypoxia is important in achieving local tumor control, and pancreatic cancers where the role of hypoxia in tumor progression has been largely uninvestigated. One way to take advantage of the decreased oxygenation status of a tumor is to administer a hypoxia-activated cytotoxin such as TPZ, which is currently being studied in Phase III clinical trials as a result from previous work in this Program Project. However, newer and more potent hypoxic cytotoxins such as PR-104, that have the additional benefit of producing a bystander effect, will be investigated in combination with cytotoxic agents such as cisplatin, inhibitors of HIF-1 which increase tumor hypoxia by shutting down mitochondrial activity and mAbs directed against CTGF and OPN that act in a cytostatic manner to inhibit tumor growth and metastases. The overall goals of this PPG are to exploit tumor hypoxia therapeutically through the inhibition of specific targets that are induced by hypoxia. Project 1 will investigate the role of HIF and CTGF in regulating tumor growth and metastases. Project 2 will investigate the efficacy of a new hypoxic cytotoxin PR-104 in combination with both cytotoxic and cytostatic agents. Project 3 will investigate mitochondrial regulation by hypoxia in yeast and mammalian cells and determine whether inhibition of HIF will increase the efficacy of hypoxic cytotoxins. Project 4 will examine the role of OPN in modulating tumor growth and metastasis. Project 5 will determine the importance of the three major signaling pathways activated by the unfolded protein response for tumor growth and adaptation to hypoxia. Few groups could be better positioned to use yeast and mammalian genetics to develop novel hypoxia based therapeutics.